JP2021109772A - Sheet feeding device, image reading device and image formation apparatus - Google Patents

Abstract

To reduce the erroneous detection of the presence/absence of a sheet loaded on a tray.SOLUTION: A sheet feeding device (200) comprises: a sheet loading part (201) which has a loading surface (201A) on which sheets are loaded; feeding means (204) which feeds the sheets in the feeding direction with a feeding roller (204); separation conveyance means (206) which separates the sheets one by one and conveys the sheets; first detection means (227) which detects that there is the sheet at a first detection position when a protrusion amount of a flag member is a first amount and detects that there is no sheet at the first detection position when the protrusion amount is a second amount; and control means (200A) which can execute the first mode that executes the first detection processing of detecting the presence/absence of the sheet before starting the descending of the feeding roller and determines the presence/absence of the sheet at the first detection position and the second mode that executes the second detection processing of detecting the presence/absence of the sheet after the descending of the feeding roller and determines the presence/absence of the sheet at the first detection position.SELECTED DRAWING: Figure 2

Description

The present invention relates to a sheet feeding device for feeding sheets, and an image reading device and an image forming device including the same.

As an image forming apparatus such as a copying machine or a facsimile, an image forming apparatus such as a scanner which optically reads an image of a document to obtain image data is known. Some of these image reading devices are provided with an automatic document feeding device (Auto Document Feeder, hereinafter referred to as ADF) so that a plurality of documents can be read by one operation. The ADF has a tray for loading paper as a document, and the separate feeding unit feeds the paper one by one from the tray to the reading unit of the image reading device (see Patent Document 1). In Patent Document 1, a sensor for detecting paper is arranged on the tray and in the vicinity of the separate feeding unit to detect the presence or absence of paper on the tray and start feeding the paper.

Japanese Unexamined Patent Publication No. 2005-247482

By the way, in recent years, it has been required for ADF to be able to supply small size paper such as business cards and checks (hereinafter referred to as small size paper). When feeding small-sized paper, the paper that is not the target of feeding may reach the separate feeding section due to the paper sticking to each other due to friction, static electricity, or the like. At this time, there is a problem that the paper is sandwiched between the separate feeding units and floats from the tray, the presence or absence of the paper on the tray is erroneously detected, and the paper to be fed remains in the tray.

The present invention has been made to solve the above problems, and an object of the present invention is to reduce erroneous detection of the presence or absence of a sheet loaded on a tray.

In order to solve the above problems, one aspect of the present invention is a sheet feeding device, and an image reading device and an image forming device including the same, a sheet loading unit having a loading surface on which sheets are loaded, and the sheet loading. It has a feeding roller that can abut and separate from the upper surface of the sheet loaded on the unit, and the sheet is fed in the feeding direction by rotating the feeding roller in a state of being in contact with the upper surface of the sheet. Separation of the feeding means to be carried out and the sheets arranged downstream of the feeding means in the feeding direction and fed from the feeding means by separating them one by one at a position separated from the loading surface. It has a transporting means and a flag member that can be moved so that the amount of protrusion with respect to the loading surface changes at the first detection position of the loading surface that overlaps with the feeding roller in the width direction orthogonal to the feeding direction. When the protruding amount of the flag member is the first amount, it is detected that the sheet is at the first detection position, and when the protruding amount of the flag member is a second amount larger than the first amount, the said. The first detection means for detecting the absence of the sheet at the first detection position and the first detection process for detecting the presence or absence of the sheet at the first detection position are executed before starting the lowering of the feeding roller. A first mode for determining the presence or absence of a sheet at the first detection position and a second detection process for detecting the presence or absence of a sheet at the first detection position after lowering the feeding roller are executed, and the first detection position is executed. It is characterized by comprising a second mode for determining the presence or absence of a sheet in the above, and a control means capable of executing the second mode.

Further, in order to solve the above problems, another aspect of the present invention includes a sheet feeding device, and an image reading device and an image forming device including the same, a sheet loading unit having a loading surface on which the sheets are loaded. It has a feeding roller that can abut and separate from the upper surface of the sheet loaded on the sheet loading portion, and the sheet is fed by rotating the feeding roller in a state of being in contact with the upper surface of the sheet. The feeding means to be fed to the vehicle and the sheets arranged downstream of the feeding means in the feeding direction and fed from the feeding means are separated one by one at a position separated from the loading surface. The separated transport means for transporting, the first detecting means for detecting the presence or absence of a sheet at the first detection position of the loading surface overlapping the feeding roller in the width direction orthogonal to the feeding direction, and the said in the width direction. A second detection means for detecting the presence or absence of a sheet at a second detection position different from the first detection position, and a first detection for detecting the presence or absence of a sheet at the first detection position before starting the descent of the feeding roller. The first mode for executing the process and determining the presence or absence of the sheet at the first detection position and the second detection process for detecting the presence or absence of the sheet at the first detection position after lowering the feeding roller are executed. The control means includes a second mode for determining the presence or absence of a seat at the first detection position, and a control means capable of executing the second detection when the seat is at the first detection position. When there is a sheet at the position, the presence / absence of the sheet is determined by the first mode, and when there is no sheet at the second detection position, the presence / absence of the sheet is determined by the second mode.

According to the present invention, it is possible to reduce erroneous detection of the presence or absence of a sheet loaded on the tray.

The schematic block diagram of the image forming apparatus of Example 1 of this disclosure. FIG. 5 is a cross-sectional view of the ADF and reader of the first embodiment. The figure (a, b) which shows the main part of the ADF of Example 1. FIG. The figure (a, b) which shows the main part of ADF at the time of seat loading of Example 1. FIG. The figure (a, b) which shows the main part of the ADF when the small-sized sheet of Example 1 is loaded. The block diagram which shows the control structure of the image forming apparatus of Example 1. FIG. It is a figure (a-e) explaining the behavior of the sheet in the feeding operation which feeds the small-sized sheet of Example 1. The flowchart which shows the flow of the feeding operation which feeds the sheet of Example 1. The figure which shows the main part of ADF as a reference example. The figures (a to d) which show the detection mode of the document in ADF as a reference example. The figure which shows the occurrence of the floating of a sheet in ADF as a reference example.

<Structure of image forming apparatus>
The configuration of the automatic document reading device 200 (hereinafter referred to as ADF200), which is the sheet feeding device of the embodiment of the present disclosure, will be described. FIG. 1 is a schematic perspective view of the image forming apparatus 300. The ADF 200 feeds the sheet to an image reader (hereinafter referred to as a reader 100) that reads the sheet as a document. The ADF 200 is provided to be openable and closable with respect to the reader 100 by an opening / closing hinge provided on the back side of the upper surface of the reader 100. Further, the ADF 200 and the reader 100 are provided on the upper surface of an image forming apparatus 300 that forms an image on a sheet by an electrophotographic or inkjet image forming means 300B. The configuration of this embodiment can also be applied to the manual feed sheet feeding means as the sheet feeding device provided in the image forming apparatus 300.

<Configuration of image reader>
Next, the configurations of the ADF 200 and the reader 100 will be described with reference to FIGS. 1 and 2. FIG. 2 is a cross-sectional view showing the configuration of the ADF 200 and the reader 100. The reader 100 includes a platen glass 101, a surface reading unit 104, an optical system motor 225 (see FIG. 6), a reading movement guide 109, and a surface white reference member 103. The surface reading unit 104 includes surface LEDs 105 and 106, a surface lens array 107, and a surface line sensor 108. The surface reading unit 104 reads the images of the sheets placed on the platen glass 101 line by line while moving along the reading movement guide 109 by the optical system motor 225. The front surface scanning glass 102 is integrally formed with the back surface white reference member 222 as shown in FIG. 2, and the front surface reading unit 104 reads an image of the sheet conveyed on the front surface scanning glass 102 by the ADF 200.

<Configuration of automatic document transfer device>
Next, the sheet feeding operation by the ADF200 will be described with reference to FIG. The ADF 200 has a loading tray 201 on which sheets are loaded, a separation roller pair 206, and a feeding roller 204 provided so as to be abutted and separated from the loading tray 201. Further, on the loading surface 201A on which the sheet is loaded on the loading tray 201, a guide surface 201S for guiding the sheet toward the nip portion 206N of the separation roller pair 206 is provided between the feeding roller 204 and the separation roller pair 206. Has been done. Further, the nip portion 206N of the separation roller pair 206 is arranged at a position higher than the loading surface 201A when viewed in the axial direction of the feeding roller 204. Further, the cover portion 228 provided so as to cover the upper portion of the feeding roller 204 is provided with an arm portion 204AM for supporting the feeding roller 204. The arm portion 204AM is arranged so as not to come into contact with the guide surface 201S when the feeding roller 204 is lowered.

The sheet loaded on the loading tray 201 as the sheet loading section is restricted from advancing downstream from the loading tray 201 before the start of feeding the sheet by the separation roller pair 206 and the feeding roller 204. The separation roller pair 206 as the separation and conveying means of this embodiment is composed of a separation upper roller 206a as a first roller forming a nip portion 206N as a separation nip portion and a separation lower roller 206b as a second roller. NS. A first document sensor 205 and a second document sensor 227 that detect the presence or absence of a sheet are provided between the separation roller pair 206 and the feed roller 204. The second sheet detecting means of this embodiment is the first document sensor 205, and the first sheet detecting means is the second document sensor 227. Then, the feeding roller 204 constituting the feeding means of the present embodiment is lowered onto the upper surface of the sheet loaded on the loading tray 201, and is rotated in a state of being in contact with the sheet to be loaded on the loading tray 201. The top sheet is delivered. The top sheet of the sheet fed by the feeding roller 204 is separated by the separation roller pair 206 and conveyed toward the inside of the ADF 200.

The sheet conveyed toward the inside of the ADF 200 by the separation roller pair 206 reaches the drawing roller pair 208. Further, in the sheet feeding direction, a feeding sensor 207 for detecting the sheet to be conveyed toward the drawing roller pair 208 is provided between the separation roller pair 206 and the drawing roller pair 208. Downstream of the drawing roller pair 208 in the sheet feeding direction, a transport path is provided in which a lead upstream roller pair 209 for transporting the sheet passing through the drawing roller pair 208 toward the surface scanning glass 102 is arranged. .. The sheet transported to the transport path is transported to the front surface reading position and the back surface reading position downstream of the lead upstream roller pair 209 by the lead upstream roller pair 209. The surface reading position is a position where the surface of the sheet is read by the surface reading unit 104. The back surface reading position is a position where the back surface of the sheet is read by the back surface reading unit 212. When reading the surface of the sheet, the sheet passes under the surface white reference member 103 integrated with the front surface scanning glass 102 by passing between the front surface scanning glass 102 and the back surface scanning glass 217. It is irradiated by the surface LEDs 105 and 106. The image of the surface of the sheet is read by reading the reflected light of the surface LEDs 105 and 106 one by one by the surface line sensor 108 through the surface lens array 107.

In the case of double-sided reading, the surface of the sheet is read by the surface reading unit 104 as described above. The back surface of the sheet is read by the back surface reading unit 212 when passing through the back surface white reference member 222 integrally formed with the front surface scanning glass 102. The back surface reading unit 212 is composed of back surface LEDs 213 and 214 and a back surface lens array 215. Then, when the sheet passes through the back surface white reference member 222, the back surface LEDs 213 and 214 irradiate the light, and the reflected light is read by the back surface line sensor 216 through the back surface lens array 215 to read the image on the back surface of the sheet. Be done. After the image is read, the sheet is conveyed to the discharge roller pair 219 by the lead downstream roller pair 218 and discharged to the discharge tray 220 by the discharge roller pair 219. When a plurality of sheets are loaded on the loading tray 201, the above-mentioned series of processes from feeding to discharging of the sheets is repeated until the surface reading of all the sheets and the discharging to the discharging tray 220 are completed. Execute. In addition to the CIS shown in FIG. 2, the front surface reading unit 104 and the back surface reading unit 212 may use a front lens array 107, a CCD composed of a reduction optical system using a mirror, or the like.

Here, as a reference example, a configuration for detecting the presence or absence of a sheet loaded on a tray in a conventional ADF will be described. FIG. 9 is a top view of the ADF 500 as a reference example. As shown in FIG. 9, in the ADF500, a sensor 504 that detects the presence or absence of the sheet P loaded on the loading tray 501 is located at the center of the loading tray 501 in the width direction orthogonal to the feeding direction of the sheet by the pickup roller 502. Have been placed. With such an arrangement, for example, even a type of sheet having a small length in the width direction such as a business card or a postcard can be detected by the sensor 504 whether or not it is loaded on the loading tray 501. .. Further, in the ADF500, the pickup roller 502 and the separation transfer means 503 are supported by the upper cover of the loading tray 501. With such a configuration, the sensor 504 is often provided on the loading tray 501 side.

For example, as shown in FIGS. 10A and 10B, when a reflective sensor such as a photoreflector is used as the sensor 504, a signal output by the sensor 504 depends on whether or not the reflected light of the irradiation light is received from the sensor 504. Changes to ON or OFF. When the sensor 504 is a photo reflector, the sensor 504 outputs an OFF signal because the amount of light reflected from the separation and transporting means 503 (broken line arrow F (a)) is small as shown in FIG. 10 (a). On the other hand, as shown in FIG. 10B, the amount of reflected light of the sheet P (broken line arrow F (b)) is detected as ON. Further, from the viewpoint of cost, as shown in FIG. 10 (c, d), a sensor 504 composed of a flag member and a photo interrupter that move up and down with respect to the loading surface of the loading tray 501 may be used. At this time, as shown in FIG. 10C, when the flag member is lowered toward the loading surface of the loading tray 501 by the sheet P, the sensor 504 outputs an ON signal. On the other hand, when the flag member rises, the sensor 504 outputs an OFF signal.

In the ADF500 having such a configuration, when sheets P and P + 1 having high rigidity such as business cards and postcards and short lengths in the feeding direction are continuously fed, the sheets as shown in FIG. 11 float. Sometimes. For example, the inclination of the transport path between the separate transport means 503 and the pickup roller 502 causes the sheet P + 1 to float above the loading surface of the loading tray 501. Further, when the sheet P + 1 is paper, the flag member of the sensor 504 rises due to the floating of the sheet P + 1 from the loading surface, and the sensor 504 is located on the loading tray 501 even though the sheet P + 1 to be fed is on the loading tray 501. Then, there is a problem of false detection if there is no sheet.

Next, with reference to FIGS. 3 to 5, a configuration for detecting the sheet loaded on the loading tray 201 in this embodiment will be described. FIG. 3A is a top view of a main part of the ADF 200 in a state where the sheet is not loaded on the loading tray 201. In the feeding direction of the sheet, between the separation roller pair 206 and the feeding roller 204, a first document sensor 205 as the second detection means of this embodiment and a second document sensor 227 as the first detection means Is provided. The detection position of the second document sensor 227, which is the first detection position of this embodiment, is arranged at the center in the width direction orthogonal to the feeding direction of the sheet. Further, the detection position of the first document sensor 205, which is the second detection position of the present embodiment, is one side in the width direction with respect to the detection position of the second document sensor 227 (width from a viewpoint facing downstream in the feeding direction). It is located on the right side of the direction). That is, the detection position of the first document sensor 205 is arranged outside the detection position of the second document sensor 227 in the width direction with respect to the center of the loading tray 201. The detection position of the first document sensor 205 may be arranged on the other side in the width direction with respect to the detection position of the second document sensor 227.

In the loading tray 201, the loading surface 201A on which the sheet is loaded is provided with regulating members 230a and 230b as sheet regulating means having a pair of regulating surfaces 231a and 231b that regulate the end portions of the sheet in the width direction. .. The regulating members 230a and 230b are movably supported on the loading surface 201A in the width direction, and the position of the feeding roller 204 in the width direction is arranged at the center of the sheet regulated by the regulating members 230a and 230b in the width direction. Has been done. Further, the detection position of the second document sensor 227 in the width direction is arranged so as to overlap the position of the feeding roller 204 in the width direction. That is, the sheet regulated by the regulating members 230a and 230b is arranged at a position that can be detected by the second document sensor 227.

FIG. 3B is a cross-sectional view of a main part of the ADF 200 in a state where the sheet is not loaded on the loading tray 201. The first document sensor 205 includes a lever portion 205A rotatably supported by the cover portion 228. The lever portion 205A is arranged so as to hang down from the cover portion 228 toward the loading surface 201A, and rotates in the feeding direction of the seat. The controller 200A (see FIG. 2) can determine whether or not there is a sheet at the detection position of the first document sensor 205 according to the amount of rotation of the lever portion 205A. When the sheet is located at the detection position of the first document sensor 205, the lever portion 205A is rotated by a predetermined amount, for example, 45 degrees in the feeding direction of the sheet, and the photo interrupter (not shown) is in a light-shielding state. The amount of rotation of the lever portion 205A when the sheet is at the detection position of the first document sensor 205 is the third amount of this embodiment. The first document sensor 205 outputs an ON signal when the position of the lever portion 205A is rotated by 45 degrees and the photo interrupter (not shown) is in a light-shielded state. Then, the controller 200A can identify that the sheet is at the detection position of the first document sensor 205 based on the received ON signal. On the other hand, when there is no sheet at the detection position of the first document sensor 205, the lever portion 205A rotates, for example, 10 degrees in the feeding direction of the sheet, and the photo interrupter (not shown) stops in a transparent state. The amount of rotation of the lever portion 205A when there is no sheet at the detection position of the first document sensor 205 is the fourth amount of this embodiment, and the fourth amount is smaller than the third amount. The first document sensor 205 outputs an OFF signal when the position of the lever portion 205A is rotated by 10 degrees and a photo interrupter (not shown) becomes a transparent state. Then, the controller 200A can identify that there is no sheet at the detection position of the first document sensor 205 based on the received OFF signal.

The second document sensor 227 includes a flag member 227A that can be moved so that the amount of protrusion with respect to the loading surface 201A changes, and a photo interrupter 229 provided below the loading surface 201A. The flag member 227A is arranged so as to project upward from below the loading surface 201A through a slit provided in the loading surface 201A, and can move in the vertical direction with respect to the loading surface 201A. When the flag member 227A moves in the vertical direction with respect to the loading surface 201A, the optical path from the light emitting portion to the light receiving portion of the photo interrupter 229 is blocked or transmitted by the flag member 227A. The controller 200A can determine whether or not there is a sheet at the detection position of the second document sensor 227 according to the amount of protrusion of the flag member 227A. When the sheet is at the detection position of the second document sensor 227, the flag member 227A moves to a position where the optical path of the photo interrupter 229 is blocked (for example, a position 5 mm below the loading surface 201A) by being pushed down by the sheet. The second document sensor 227 outputs an ON signal when the optical path of the photo interrupter 229 is blocked, and the controller 200A identifies that the sheet is at the detection position of the second document sensor 227 based on the received ON signal. can do. The amount of protrusion of the flag member 227A with respect to the loading surface 201A when the sheet is at the detection position of the second document sensor 227 is the first amount of this embodiment. The first amount of the present embodiment includes the amount of protrusion of the flag member 227A with respect to the loading surface 201A, that is, the amount of protrusion of the flag member 227A when the flag member 227A does not protrude from the loading surface 201A. ..

On the other hand, when there is no sheet at the detection position of the second document sensor 227 (see FIG. 3B), the flag member 227A is in a state where it cannot be pushed down by the sheet. At this time, the flag member 227A moves to a position where the optical path of the photointerruptor 229 is transmitted (for example, a position 5 mm above the loading surface 201A). The second document sensor 227 outputs an OFF signal when the optical path of the photo interrupter 229 is in a transmitted state, and the controller 200A identifies that there is no sheet at the detection position of the second document sensor 227 based on the received OFF signal. can do. The amount of protrusion of the flag member 227A with respect to the loading surface 201A when there is no sheet at the detection position of the second document sensor 227 is the second amount of this embodiment, and the second amount is larger than the first amount. Further, when the feeding roller 204 is lowered toward the loading tray 201, the feeding roller 204 is lowered so that the relative position with respect to the flag member 227A is a position through which the optical path of the photointerruptor 229 is transmitted by the flag member 227A.

In this way, the ADF 200 can detect the presence or absence of the sheet at the detection positions of the first document sensor 205 and the second document sensor 227 provided at different positions in the width direction of the sheet. Then, the controller 200A can determine the presence / absence of the sheet on the loading tray 201 and the size of the loaded sheet based on the detection signals output from the first document sensor 205 and the second document sensor 227.

Next, a configuration for determining the size of the sheet loaded on the loading tray 201 in this embodiment will be described. The length W in the width direction in FIGS. 4 (a) and 5 (a) is the length of the feeding roller 204 in the width direction. FIG. 4A is a top view of the ADF 200 when a sheet S having a sheet width longer than the length W in the width direction is loaded on the loading tray 201. At this time, it is detected that the sheet is present at the detection positions of both the first document sensor 205 and the second document sensor 227, and both the first document sensor 205 and the second document sensor 227 output an ON signal. According to the controller 200A, when both the first document sensor 205 and the second document sensor 227 output an ON signal, a sheet S having a sheet width longer than the length W in the width direction is loaded on the loading tray 201. to decide.

FIG. 4B is a cross-sectional view of the vicinity of the separation roller pair 206 when the seat S is loaded. As described above, the first document sensor 205 outputs an ON signal when the lever portion 205A is rotated by a predetermined amount by the sheet. When the tip of the sheet S is pushed below the feeding roller 204, the end of the sheet S becomes a position overlapping the detection position of the first document sensor 205 in the width direction. As a result, the lever portion 205A of the first document sensor 205 is rotated by the sheet S toward the downstream (direction of arrow F1 in FIG. 4B) in the feeding direction of the sheet, and the photo interrupter (not shown) is in a light-shielded state. Become. As a result, the first document sensor 205 outputs an ON signal. As described above, the second document sensor 227 outputs an ON signal when the flag member 227A is pushed down by the sheet S and moves to a position where the optical path of the photointerruptor 229 is blocked. When the tip of the sheet S is pushed below the feeding roller 204, the flag member 227A of the second document sensor 227 moves downward with respect to the loading surface 501A, and the photo interrupter 229 is shaded by the flag member 227A. As a result, the second document sensor 227 outputs an ON signal. As described above, in the controller 200A, since both the first document sensor 205 and the second document sensor 227 output an ON signal, the loading tray 201 has a sheet S having a sheet width longer than the length W in the width direction. Judge that it is loaded.

FIG. 5A is a top view of the ADF 200 when a sheet K having a sheet width shorter than the length W in the width direction is loaded on the loading tray 201. In this embodiment, the size of the sheet K whose sheet width in the width direction is shorter than the length W is defined as "small size". The position of the sheet K in the loading tray 201 is regulated by the regulating members 230a and 230b so that the center of the sheet K in the width direction is the center position of the feeding roller 204 in the width direction. At this time, while it is detected that the sheet is present at the detection position of the second document sensor 227, the edge of the sheet K does not reach the detection position of the first document sensor 205, so that the first document sensor 205 It is detected that there is no sheet at the detection position of. That is, the first document sensor 205 outputs an OFF signal, and the second document sensor 227 outputs an ON signal. The controller 200A has a small size in which the sheet width in the width direction is shorter than the length W on the loading tray 201 when the first document sensor 205 outputs an OFF signal and the second document sensor 227 outputs an ON signal. It is determined that the sheet K is loaded.

FIG. 5B is a cross-sectional view of the vicinity of the separation roller pair 206 when the sheet K is loaded. As described above, the first document sensor 205 outputs an ON signal when the lever portion 205A is rotated by a predetermined amount by the sheet. When the tip of the sheet K is pushed below the feeding roller 204, the end of the sheet K does not reach the detection position of the first document sensor 205. That is, in the width direction, the end portion of the sheet K is at a position that does not overlap with the detection position of the first document sensor 205. As a result, the lever portion 205A of the first document sensor 205 is in a state of stopping with the photo interrupter (not shown) in a transparent state, and the first document sensor 205 outputs an OFF signal. On the other hand, as described above, the second document sensor 227 outputs an ON signal when the flag member 227A is pushed down by the sheet and moved to a position where the optical path of the photointerruptor 229 is blocked. When the tip of the sheet K is pushed below the feeding roller 204, the flag member 227A of the second document sensor 227 moves downward with respect to the loading surface 501A, and the photo interrupter 229 is shaded by the flag member 227A. As a result, the second document sensor 227 outputs an ON signal. In this way, since the first document sensor 205 outputs the OFF signal and the second document sensor 227 outputs the ON signal, the controller 200A has the sheet width in the width direction of the loading tray 201 from the length W. It is judged that the short sheet K is loaded. The sheet width of the sheet K as the second width in this embodiment is, for example, the width of the minimum size sheet that can be regulated by the regulating members 230a and 230b, the sheet width of the business card size sheet, and the like. be. Further, the sheet width of the length W in the width direction as the first width of this embodiment is equal to or larger than the minimum size sheet width that can be regulated by the regulating members 230a and 230b, the sheet width of the business card size sheet, and the like. The width of. That is, in this embodiment, the second width is a sheet width shorter than the first width, and is the sheet width when the edge portion of the sheet in the width direction does not overlap the detection position of the first document sensor 205. .. Further, in the present embodiment, the first width is the sheet width when the edge portion of the sheet in the width direction overlaps the detection position of the first document sensor 205.

<Control configuration>
Next, a configuration for controlling the operation of the ADF 200 will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration for controlling the operation of the ADF 200. As shown in FIG. 6, the ADF 200 and the image forming apparatus 300 are electrically connected by buses 401 and 402.

<Controller configuration on the ADF side>
First, a configuration for controlling the operation of the reader 100 and the ADF 200 will be described. The controller 200A as a control means for controlling the operation of the reader 100 and the ADF 200 includes a CPU 301, a ROM 302, a RAM 303, an image transfer unit 304, an image memory 305, and an image processing unit 306. The CPU 301 is a calculation means and executes a program that controls the operations of the reader 100 and the ADF 200. The ROM 302 is a non-volatile storage area, and stores the control programs of the reader 100 and the ADF 200. The RAM 303 is a storage area used as a work area when the CPU 301 performs an operation. The CPU 301 loads the program stored in the ROM 302, expands it into the RAM 303, and executes the program expanded in the RAM 303 to control the operations of the reader 100 and the ADF 200 in the controller 200A.

A transfer motor 224 for driving each roller that conveys a sheet in the ADF 200 is connected to the CPU 301. The transfer motor 224 is connected to the feed roller 204 and the separation roller pair 206 via the separation clutch 223. By disengaging the separation clutch 223, the sheet can be held in a state where the sheet transfer is stopped at the position PS (see FIG. 2) before reaching the drawing roller pair 208. Further, the CPU 301 is connected to the first document sensor 205, the second document sensor 227, the feed sensor 207, and the read sensor 210. The feed sensor 207 and the lead sensor 210 are sensors that detect the edge of the sheet at the detection position inside the ADF200. In this embodiment, the transfer motor 224 is a pulse motor, and the CPU 301 controls the number of drive pulses to manage the pulses of the transfer motor 224. The number of drive pulses can be converted as the transfer distance of the sheet to be conveyed by the ADF 200, and the CPU 301 controls the transfer of the sheet based on the transfer distance of the sheet calculated based on the number of drive pulses of the transfer motor 224.

The CPU 301 is connected to an optical system motor 225 for moving the surface reading unit 104 in the sub-scanning direction, an optical system HP sensor 226, an image memory 305, an image processing unit 306, and an image transfer unit 304. There is. The front surface reading unit 104 and the back surface reading unit 212 scan the sheet and read the image of the sheet line by line. The image memory 305 is a storage area for temporarily storing the image data of the sheet read by the front surface reading unit 104 and the back surface reading unit 212. The image processing unit 306 performs image processing on the image data stored in the image memory 305. The image transfer unit 304 transfers the image data processed by the image processing unit 306 to the image transfer unit 314 of the controller 310 via the bus 402.

<Configuration of controller on the main unit>
Next, the configuration of the controller 300A as the main body side control means for controlling the operation of the entire image forming apparatus 300 will be described. The controller 300A controls the operation of the entire image forming apparatus 300 as an image reading system including the reader 100 and the ADF 200. The controller 300A is communicably connected to the controller 200A, and controls the operation of the image forming apparatus 300 based on the signal input from the controller 200A. Further, the controller 300A outputs a signal for controlling the operation of the reader 100 and the ADF 200 to the controller 200A.

The controller 300A includes a CPU 311, a ROM 312, a RAM 313, an image transfer unit 314, and an image memory 315. The CPU 311 is a calculation means on the main body side of the image forming apparatus 300, and executes a program for controlling the operation of the entire image forming apparatus 300. The ROM 312 is a non-volatile storage area, and stores a control program of the image forming apparatus 300. The RAM 313 is a storage area used as a work area when the CPU 310 performs an operation. The CPU 311 loads the program stored in the ROM 312, expands it into the RAM 313, and executes the program expanded in the RAM 313 to control the operation of the image forming apparatus 300 in the controller 300A. The operation of the image forming apparatus 300 is, for example, an image forming operation in the image forming means 300B. The image transfer unit 314 receives an image from the image transfer unit 304 and stores it in the image memory 315. The image forming apparatus 300 is provided with an operation unit 316 that gives an operation instruction to the image forming apparatus 300, the reader 100, and the ADF 200 from the user, displays a message to the user, and displays the read image. The operation unit 316 communicates with the CPU 311 and outputs information regarding an image display and an operation instruction of the image forming apparatus 300 to the CPU 311.

The CPU 311 communicates with the CPU 301 via the bus 401 to exchange control commands related to the image reading operation of the reader 100 and the ADF 200 and input / output control data. For example, the CPU 311 receives information instructing the start of image reading in the reader 100 and the ADF 200 from the operation unit 316, and outputs information requesting the start of image reading to the CPU 301. For example, the CPU 311 receives the sheet size setting information by the user from the operation unit 316, and transmits the sheet size (sheet length in the feeding direction and the width direction) information to the CPU 301. Further, the CPU 311 receives information from the CPU 301 indicating that an abnormality has occurred in the reader 100 and the ADF 200, and notifies the operation unit 316 of a message to the user according to the type of abnormality.

Next, in this embodiment, the behavior of the sheet K in the feeding operation of feeding the small-sized sheet K will be described. 7 (a) to 7 (d) are explanatory views of the behavior of the sheet K in the feeding operation. In FIGS. 7A to 7D, the vicinity of the feeding roller 204 and the separation roller pair 206 is enlarged and shown. As shown in FIG. 7A, when the separation clutch 223 is turned on, the feed roller 204 rotates in the direction of arrow r as the transfer motor 224 is driven. Further, when the separation clutch 223 is turned on and connected to the transfer motor 224, the feed roller 204 descends to the loading tray 201, picks up the topmost sheet K of the sheet bundle on the loading tray 201, and has a broken line arrow. Feed in the direction of D.

As shown in FIG. 7B, when the tip of the sheet K passes through the separation roller pair 206 and reaches the extraction roller pair 208, the separation clutch 223 is turned off and the rotation of the feeding roller 204 is stopped. This is to prevent the sheet K + 1 to be fed next from being fed immediately after the sheet K has passed through the feeding roller 204. However, as shown in FIG. 7B, when a small-sized sheet such as the sheet K is fed, the sheet is before the tip of the sheet K reaches the pull-out roller pair 208 and stops the rotation of the pickup roller. The rear end of K passes through the feeding roller 204. As a result, since the feeding roller 204 comes into contact with the next sheet K + 1 in the rotated state, the sheet K + 1 is transported in the direction of the broken line arrow D along with the transportation of the sheet K, so-called transporting occurs. Such behavior in small size sheets is not limited to short sheet lengths in the feeding direction. For example, if the sheet is made of a material with low friction, or if the front and rear sheets are stuck together due to static electricity or the like, there is a possibility that the sheet will be carried as shown in FIG. 7 (b). be.

Then, as shown in FIG. 7C, the sheet is lifted due to the feeding of the sheet. When the tip of the sheet K, which is fed prior to the sheet transport path, reaches the drawing roller pair 208, the rotation of the feeding roller 204 is stopped. The sheet K that has reached the drawing roller pair 208 is conveyed by the drawing roller pair 208 and the rollers arranged downstream of the transfer path. Further, the rotations of the feeding roller 204 and the separation roller pair 206 are interlocked by the separation clutch 223. On the loading surface 201A of the loading tray 201, a guide surface 201S for guiding the tip of the sheet toward the nip portion 206N of the separation roller pair 206 is provided between the feeding roller 204 and the separation roller pair 206. Further, the nip portion 206N of the separation roller pair 206 is arranged at a position higher than the loading surface 201A. With such a configuration, it is possible to suppress the entry of the entire bundle of sheets loaded on the loading tray 201 to the downstream, and to supply only the highest-level sheet to the transport path. When the sheet is transported when the sheet is fed, the rear end of the transported sheet may be lifted while the tip of the transported sheet is in contact with the nip portion 206N of the separation roller vs. 206. .. In this embodiment, the state in which the rear end of the sheet floats from the loading surface 201A when the tip of the sheet reaches the separation roller pair 206 is referred to as "floating of the sheet". At this time, since the separation clutch 223 is in the OFF state, the feeding roller 204 is in a non-rotating state like the separation roller pair 206, and does not have the power to move downward. As described above, when the sheet is floated, the feeding roller 204 is in a state of being separated from the loading surface 201A.

FIG. 7D shows a state in which the feeding of the seats is continued in a state where the feeding of the seats has occurred, and the feeding of the seats K + 2 has occurred in the feeding of the seats K + 1. Of the sheets loaded on the loading tray 201, the last sheet, sheet K + 2, is transported at the time of feeding the sheet K + 1 to be fed, so that the tip of the sheet K + 2 reaches the separation roller pair 206. Then, when the rear end of the sheet K + 1 passes through the feeding sensor 207, the feeding of the next sheet K + 2 is started. At this time, before lowering the feeding roller 204 to start feeding the sheet, the presence or absence of the sheet on the loading tray 201 is determined based on the detection result of the second document sensor 227. The first detection process of this embodiment is a process of detecting the presence or absence of a sheet on the loading tray 201 by the second document sensor 227 before lowering the feeding roller 204. Further, the first mode of this embodiment is an operation mode for determining the presence or absence of a sheet at the detection position of the second document sensor 227 on the loading tray 201 before lowering the feeding roller 204.

However, in this case, since the flag member 227A of the second document sensor 227 is moved in the direction of the broken line arrow f1 in FIG. 7 (d) due to the floating of the sheet K + 2, the sheet is moved to the detection position of the second document sensor 227. It is judged that there is no such thing. In this way, when the sheet is carried away, even though the sheet to be fed remains in the loading tray 201, it is erroneously detected that there is no sheet, and the sheet K + 2 is not fed. A situation may occur in which the product remains in the loading tray 201.

On the other hand, in this embodiment, as shown in FIG. 7E, the presence or absence of the sheet on the loading tray 201 is determined based on the detection result of the second document sensor 227 after lowering the feeding roller 204. do. Specifically, first, the separation clutch 223 is turned on, the feeding roller 204 is lowered, and the feed roller 204 is pressed against the seat K + 2. When the sheet K + 2 is pushed down by the feeding roller 204, the flag member 227A of the second document sensor 227 moves downward (in the direction of arrow f2) with respect to the loading surface 201A. Then, after the floating of the sheet K + 2 is eliminated by the feeding roller 204, the presence or absence of the sheet on the loading tray 201 is determined based on the detection result of the second document sensor 227. The second detection process of this embodiment is a process of lowering the feeding roller 204 and then detecting the presence or absence of a sheet on the loading tray 201 by the second document sensor 227. Further, the second mode of this embodiment is a small-sized transport mode in which the presence or absence of a sheet at the detection position of the second document sensor 227 on the loading tray 201 is determined after the feed roller 204 is lowered. In addition, the small size transport mode may be configured to perform the first detection process and then the second detection process.

In this way, when there is a sheet on the loading tray 201 in the small size transport mode, the flag member 227A moves due to the lowering of the feeding roller 204, so that the second document sensor 27 outputs an ON signal. On the other hand, when there is no sheet in the loading tray 201 in the small size transport mode, the flag member 227A does not move even if the feeding roller 204 is lowered, so that the signal of the second document sensor 227 remains OFF. As described above, in this embodiment, since the presence / absence of the sheet on the loading tray 201 is detected after the floating of the sheet is eliminated, it is possible to reduce the false detection of the presence / absence of the sheet on the loading tray 201.

<Flow of sheet feeding operation>
Next, in this embodiment, the flow of the feeding operation of feeding the sheets from the loading tray 201 will be described with reference to FIG. FIG. 8 is a flowchart showing a flow of a feeding operation for feeding the sheets loaded on the loading tray 201 in this embodiment. The sheet feeding operation according to the flowchart of FIG. 8 is an operation mainly executed by the controller 200A when the CPU 301 executes a program stored in the ROM 302. The flowchart of FIG. 8 can be similarly applied to the feeding operation when the image of the sheet is read for one side and both sides.

When the user instructs the start of the reading process for reading the image of the sheet by operating the operation unit 316 or the like, the CPU 311 of the controller 300A outputs a signal for starting the reading process to the controller 200A, and this flow Is started. When a signal for starting the scanning process is input to the controller 200A, the signal of the first document sensor 205 is confirmed (S101). When the first document sensor 205 outputs an ON signal (S101 / Y), it is determined that the sheet loaded on the loading tray 201 is not a small size sheet, and the small size transfer mode is turned off in the RAM 303. The information to be stored is stored (S102). On the other hand, when the first document sensor 205 outputs an OFF signal (S101 / N) and the second document sensor 227 outputs an ON signal (S115 / Y), the sheet loaded on the loading tray 201. Is judged to be a small size sheet. Then, the information for turning on the small size transfer mode is stored in the RAM 303 (S116).

Next, in order to feed the sheet from the loading tray 201, the transfer motor 224 is driven (S103) and the separation clutch 223 is turned on (S104). As a result, the feeding roller 204 descends to the sheet loaded on the loading tray 201, and the feeding roller 204 rotates in a state of being in contact with the upper surface of the sheet. Then, the sheet is fed to the separation roller pair 206 by the feeding roller 204, and the sheets are separated one by one by the separation roller pair 206 and conveyed toward the drawing roller pair 208. When the feed sensor 207 outputs an ON signal (S105 / Y), it is determined that the sheet has reached the drawing roller pair 208 (S106). When the seat reaches the pull-out roller pair 208, the separation clutch 223 is turned off (S107) to stop the rotation of the feed roller 204 and the separation roller pair 206. The sheet that has reached the drawing roller pair 208 is conveyed toward the surface reading position, and the image of the surface of the sheet is read by the surface reading unit 104. When reading the image on both sides of the sheet, after reading the image on the front side, the image on the back side is read by the back side reading unit 212 at the back side reading position. When the output signal of the feed sensor 207 is switched from ON to OFF by the sheet being conveyed by the drawing roller pair 208 (S108 / Y), the small size transfer mode is in the ON state or the OFF state with reference to the RAM 303. Confirm which is the case (S109).

When the small size transfer mode is ON (S109 / Y), it is known that the sheet loaded on the loading tray 201 is a small size sheet. Therefore, before the presence / absence of the sheet is detected by the second document sensor 227, the separation clutch 223 is turned on (S110) and the feeding roller 204 is lowered (S111). At this time, the feed roller 204 descends toward the sheet loaded on the loading tray 201, so that the sheet is pushed down toward the loading surface 201A of the loading tray 201. As described above, when the small size transport mode is in the ON state, the feeding roller 204 is lowered to push down the seat, thereby eliminating the floating of the seat from the loading surface 201A. As a result, among the sheets loaded on the loading tray 201, the sheet is pushed down by the feeding roller 204 even when the flag member 227A of the second document sensor 227 is located above the loading surface 201A due to the floating of the final sheet. Will be done. Then, by pushing down the sheet, the flag member 227A of the second document sensor 227 moves below the loading surface 201A, and the output signal of the second document sensor 227 is switched from the OFF signal to the ON signal. In S111, the feeding roller 204 is lowered to the same position as when the seat is fed.

When the lowering of the feeding roller 204 is completed (S111 / Y), the output signal of the second document sensor 227 is confirmed (S112). When the second document sensor 227 outputs an ON signal (S112 / N), since there is a sheet on the loading tray 201, the process returns to S105 and the steps from S105 to S111 are continued until the loading tray 201 runs out of sheets. Repeat. As described above, in this embodiment, when it is detected that the sheet loaded on the loading tray 201 is a small size sheet, the feeding roller 204 is lowered and then the presence or absence of the sheet on the loading tray 201 is determined. determine. When the second document sensor 227 outputs an OFF signal (S112 / Y), there is no sheet in the loading tray 201. In this case, the separation clutch 223 is turned off (S113), the transfer motor 224 is stopped (S114), and a series of feeding operations is completed.

On the other hand, in S109, when the small size transfer mode is in the OFF state (S109 / N), it is known that the sheet loaded on the loading tray 201 is not a small size. In such a case, it is assumed that the sheet has not floated with respect to the loading surface 201A, and the output signal of the first document sensor 205 is confirmed before starting the lowering of the feeding roller 204 (S117). When the first document sensor 205 outputs an ON signal (S117 / N), since the sheet on the loading tray 201 remains, it returns to S104 and the steps from S104 to S109 are transferred to the loading tray 201. Repeat until there is no more. As described above, in this embodiment, when it is detected that the sheet loaded on the loading tray 201 is not a small-sized sheet, the feeding roller 204 is lowered and then the presence or absence of the sheet on the loading tray 201 is determined. determine. On the other hand, when the first document sensor 205 outputs an OFF signal (S117 / Y), since there is no sheet in the loading tray 201, the transfer motor 224 is stopped (S114) to supply a series of feeds. End the feed operation. When both the first document sensor 205 and the second document sensor 227 output an OFF signal (S101 / N and S115 / N) after the start of the scanning process, the sheet is placed on the platen glass 101. The image of the sheet is read in this state. Then, after the image of the sheet is read, this process ends (FIGS. 8, A).

As described above, in the present embodiment, when the sheet loaded on the loading tray 201 is lifted, the feeding roller 204 is lowered to eliminate the floating of the sheet, and then the presence or absence of the sheet on the loading tray 201 is eliminated. Is detected. Therefore, it is possible to reduce erroneous detection of the presence or absence of a sheet on the loading tray 201 due to the floating of the sheet.
<Other Examples>

As the second document sensor 227, in the first embodiment, a configuration for detecting the presence or absence of a sheet by blocking or setting the optical path of the photo interrupter 229 in a transparent state by the flag member 227A has been described. As the second document sensor 227, a sensor such as a photo reflector that irradiates the sheet with light and detects the presence or absence of the sheet according to the amount of reflected light from the sheet may be used. Even when the second document sensor 227 is a photo reflector, by pushing down the sheet by the feeding roller 204, it is possible to reduce erroneous detection of the presence or absence of the sheet due to the floating of the sheet.

100: Reader (image reader) / 200: ADF (seat feeder) / 200A: Controller (control means) / 201: Loading tray (sheet loading unit) / 201A: Loading surface / 201S: Guide surface / 204: Supply Feed roller (feeding means) / 204AM: Arm part / 205: First document sensor (second detecting means) / 205A: Lever part / 206: Separation roller pair (separation transport means) / 206a: Separation upper roller (first) Roller) / 206b: Separation lower roller (second roller) / 206N: Nip part (separation nip part) / 227: Second document sensor (first detection means) / 227A: Flag member / 228: Cover part / 229: Photo Interruptors / 230a, 230b: Regulatory members / 231a, 231b: Regulatory surfaces / 300: Image forming apparatus / 300B: Image forming means

Claims (11)

A seat loading section with a loading surface on which the seat is loaded,
It has a feeding roller that can abut and separate from the upper surface of the sheet loaded on the sheet loading portion, and the sheet is fed by rotating the feeding roller in a state of being in contact with the upper surface of the sheet. And the means of delivery
A separate transport means that is arranged downstream of the feed means in the feed direction and that separates and transports the sheets fed from the feed means one by one at a position separated from the loading surface.
The flag member has a flag member that can be moved so that the amount of protrusion with respect to the loading surface changes at the first detection position of the loading surface that overlaps with the feeding roller in the width direction orthogonal to the feeding direction. When the protrusion amount is the first amount, it is detected that the sheet is at the first detection position, and when the protrusion amount of the flag member is a second amount larger than the first amount, the first detection position. The first detection means to detect that there is no sheet in the
A first mode in which a first detection process for detecting the presence or absence of a sheet at the first detection position is executed before the lowering of the feeding roller is started to determine the presence or absence of a sheet at the first detection position, and the supply. A control means capable of executing a second detection process for detecting the presence or absence of a sheet at the first detection position after lowering the feed roller and determining the presence or absence of a sheet at the first detection position. And with
A sheet feeding device characterized by that. A second detection means for detecting the presence or absence of a sheet at a second detection position different from the first detection position in the width direction is provided.
When the first detection means detects that the seat is at the first detection position, the control means detects that the seat is at the second detection position by the second detection means. The presence or absence of a sheet is determined by the first mode, and the presence or absence of a sheet is determined by the second mode when it is detected by the second detection means that there is no sheet at the second detection position.
The sheet feeding device according to claim 1. The second detection position is arranged outside the first detection position in the width direction.
The sheet feeding device according to claim 2, wherein the sheet feeding device is characterized in that. A cover portion that covers the upper part of the feeding roller is provided.
The second detection means has a lever portion that is rotatably supported by the cover portion and rotates in the feeding direction, and the second detection means when the rotation amount of the lever portion is a third amount. It detects that there is a sheet at the position, and detects that there is no sheet at the second detection position when the rotation amount of the lever portion is a fourth amount smaller than the third amount.
The sheet feeding device according to claim 2 or 3, wherein the sheet feeding device according to claim 2 or 3. The control means executes the first mode when a sheet having a sheet width of the first width is loaded on the loading surface, and the sheet having a sheet width shorter than the first width has a second width. It is configured to execute the second mode when it is loaded on the loading surface.
The sheet feeding device according to any one of claims 1 to 4, wherein the sheet feeding device is characterized. The separation and transportation means has a first roller and a second roller, and in the separation nip portion formed by the first roller and the second roller, one sheet is fed from the feeding means one by one. To separate,
The sheet feeding device according to any one of claims 1 to 5, wherein the sheet feeding device is characterized. The feeding means has an arm portion that supports the feeding roller, and has an arm portion.
The sheet loading portion has a guide surface that is inclined from the loading surface toward the separated transport means and guides the tip of the sheet toward the separated nip portion.
The guide surface is arranged so as not to come into contact with the arm portion when the feeding roller is lowered.
The sheet feeding device according to claim 6, wherein the sheet feeding device is characterized in that. A sheet regulating means having a pair of regulating surfaces for regulating the end portion of the sheet in the width direction and being movably supported on the loading surface in the width direction is provided.
The feed roller is arranged in the center of the sheet regulated by the sheet regulating means in the width direction.
The sheet feeding device according to any one of claims 1 to 7, wherein the sheet feeding device is characterized. A seat loading section with a loading surface on which the seat is loaded,
It has a feeding roller that can abut and separate from the upper surface of the sheet loaded on the sheet loading portion, and the sheet is fed by rotating the feeding roller in a state of being in contact with the upper surface of the sheet. And the means of delivery
A separate transport means that is arranged downstream of the feed means in the feed direction and that separates and transports the sheets fed from the feed means one by one at a position separated from the loading surface.
A first detecting means for detecting the presence or absence of a sheet at a first detecting position of the loading surface overlapping the feeding roller in a width direction orthogonal to the feeding direction.
A second detection means for detecting the presence or absence of a sheet at a second detection position different from the first detection position in the width direction, and
A first mode in which a first detection process for detecting the presence or absence of a sheet at the first detection position is executed before the lowering of the feeding roller is started to determine the presence or absence of a sheet at the first detection position, and the supply. A control means capable of executing a second detection process for detecting the presence or absence of a sheet at the first detection position after lowering the feed roller and determining the presence or absence of a sheet at the first detection position. And with
When the control means has a sheet at the first detection position, the presence or absence of the sheet is determined by the first mode when the sheet is present at the second detection position, and when there is no sheet at the second detection position. The presence or absence of the sheet is determined by the second mode.
A sheet feeding device characterized by that. The sheet feeding device according to any one of claims 1 to 9,
An image reading means for reading a sheet fed by the sheet feeding device is provided.
An image reader characterized by this. The image reading device according to claim 10,
An image forming means for forming an image on a sheet based on an image read by the image reading device is provided.
An image forming apparatus characterized in that.

Images